Method and apparatus for treating blood



Aug. 19, 1969 T. J. GREENWALT ET 3,462,361

METHOD AND APPARATUS FQR TREATING BLOOD Filed May 14. 1965 w r w R s m q as Var-v 5 WPWMW n a 5m 1w m a d mm 4 M United States Patent 3,462,361 METHOD AND APPARATUS FOR TREATING BLOOD Tibor .I. Greenwalt, Milwaukee, Wis., and Mieczyslaw Gajewski, Pittsburgh, Pa, assignors to Milwaukee Blood Center, Inc., Milwaukee, Wis., a corporation of Wisconsin Continuation-impart of application Ser. No. 129,737, Aug. 7, 1961. This application May 14, 1965, Ser.

Int. Cl. B01d 13/00 US. Cl. 21023 16 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus for treating blood in which the leukocytes are removed from the whole blood by adsorption on a column of fibers. The whole blood having a pH in the range of 7.3 to 7.5 is passed through a column of haphazardly arranged, loosely compacted synthetic fibers having a bulk density of 2.5 to 7.5 grams per cubic inch to remove the leukoctyes from the blood by both mechanical filtering and polar attraction.

This application is a continuation-in-part of application Ser. No. 129,737, filed Aug. 7, 1961, and entitled, Method and Apparatus For Treating Blood, now abandoned.

This invention relates to a method and apparatus for treating animal blood and more particularly to a method and apparatus for removing the white blood cells from animal blood.

Between five and six million blood transfusions are administered annually in the United States. In cases where the patient receives multiple transfusions or during pregnancy, febrile transfusion reactions may occur. Dispite efforts to eliminate bacterial pyrogens from the transfusion equipment, febrile transfusion reaction occur in more than 1% of all transfusions. The febrile transfusion reactions are generally due to sensitization by leukocyte antigens and the severity of the reaction varies from chilliness followed by a moderate rise in temperature to shaking chills and fever exceeding 105 F., accompanied by headache, backache, cyanosis and dyspnea. This type of reaction can be prevented by administering blood from which the white blood cells or leukocytes have been substantially removed.

Various processes have been described in the literature for obtaining leukocyte suspensions for the purpose of studying the white blood cells. These processes generally are applicable only to small volumes of blood, such as that obtained by magnetic separations, or require the ad ditions of substances which cannot be injected into the human body, or are expensive and potentially dangerous to the body, such as those employing fibrinogen, dextran, polyvinylpyrrolidone, or acacia.

In the past, blood has been treated to remove the buffy layer or white blood cells for transfusion purposes by ditferential sedimentation in the presence of dextran or differential centrifugation processes. Processes of this type for removal of white blood cells have several disadvantages in that special containers and expensive refrigerated centrifuges are needed, and it requires a substantial period of time for the separation to be completed, normally in the range of 2 to 4 hours. As the blood must be handled and introduced and withdrawn from the separating equipment, the hazard of contamination is greatly increased.

With the normal centrifugation or sedimentation type of removal, the blood platelets are lost and Ma to /2 of the red blood cells and all of the plasma are discarded 3,462,361 Patented Aug. 19, 1969 during the operation. Furthermore, the final white blood count in the treated blood is uncertain and unpredictable.

The final product to be used for transfusion after the separation of the white blood cells by the normal centrifugal process is a suspension of the red cells in saline, and in some cases the saline suspensions are not suitable for use with patients who are bleeding actively or during surgery. Furthermore, the storage of these preparations is necessarily limited to a few hours and beyond that time the treated blood cannot be used.

The present invention is directed to a method and apparatus for treating animal blood in which the leukocytes or white blood cells are removed from the whole blood by adsorption on a column of fibers. More specifically, the whole blood having a pH in the range of 7.3 to 7.5 is passed through a column of loosely compacted fibers. The fibers are pretreated to remove the surface finish, and by employing a fiber column of predetermined density and using gravity or a given vacuum, blood is drawn through the fibers and the white blood cells are susbtantially eliminated. The white blood cells are removed not only by mechanical filtering of the fibers, but by polar or electrostatic attraction.

The equipment of the invention is inexpensive and provides a very rapid separation of the white blood cells without an appreciable loss of the other constituents of the blood. By the method of the invention, a pint of blood can be treated in a period of 10 to 15 minutes or less as opposed to the normal treating procedure by centrifugal methods of 2 to 4 hours. Moreover, the apparatus of the invention is of very simple construction and no special containers or refrigerated equipment are required.

The handling of the blood is reduced to a minimum with the process of the invention and the danger of contamination is practically nonexistent.

The final product contains the red blood cells, the plasma and most of the platelets, with only the white blood cells being removed. Furthermore, the loss of the donor blood is reduced from about 30 to 50% with the use of the conventional processes to about 5% with the method of the invention.

The White blood count of the treated blood is uniform and predictable so that each batch of treated blood has substantially the same white blood count. Present evidence has indicated that the blood treated in the manner of the invention can be safely stored for periods of at least 14 days and this is a substantial increase in the storage period over blood treated by conventional centrifugal methods wherein the blood must be utilized within several hours after treatment.

Other objects and advantages will appear in the course of the following description.

The drawings illustrate the best mode presently contemplated of carrying out the invention.

In the drawings:

FIG. 1 is a plan view of the filter assembly of the invention;

FIG. 2 is a plan view showing the filter assembly connecting two bottles;

FIG. 3 is a view showing the filter assembly employed in combination with plastic bags; and

FIG. 4 is a modified form of the invention showing the incorporation of an ion exchange resin pack in com bination with the blood treating apparatus of FIG. 3.

FIG. 1 shows a filter assembly which includes a tube 1 having an open end enclosed by a rubber stopper 2. The tube 1 is generally formed of a transparent material such as glass or plastic and contains a mass or column of haphazardly arranged fibers 3 through which the whole blood from the donor is adapted to pass during the process of the invention.

An inlet tube 4 is sealed within an opening in stopper 2 and a flexible tube 5 connects the inlet tube with a needle 6. The lower end of the tube 4 is provided with an outlet nipple 7 which is connected by a flexible tube 8 to a needle 9.

The fibers 3, which are disposed within tube 1 are formed of a synthetic material, such as nylon, Orlon (a polymer of acrylonitrile), Dacron (polyester), Teflon (polytetrafiuoroethylene), or the like. It is desired that the fibers be flexible and not fragile, such as glass fibers, and that the fibers be relatively non-absorbent so that the blood will not be absorbed in the fibers themselves as the blood passes through tube 1.

The synthetic fibers, as obtained from the manufacturer, will not function to effectively remove the white blood cells from the blood, and thus the fibers must be treated to remove the sizing or surface finish. Generally, the fibers are washed in an aqueous solution of a surface active agent, such as a 1% solution of Duponol, which is a mixture of sodium salts of sulfated fatty alcohols. The fibers are maintained in contact with the surface active agent for a period of about 20 minutes at a tempera ture of 70 C. to 75 C. to remove the surface finish applied by the manufacturer. Other surface active agents can be employed in place of Duponol for removing the surface finish.

The fibers are then washed for about 20 minutes in hot distilled water, rinsed in cold distilled water, and dried in an oven to evaporate the moisture.

The treated fibers as packed in the tube 1 have a bulk density in the range of 2.5 to 7.5 grams/ cubic inch and preferably the fibers have a compaction equivalent to that of 20 grams of fibers having an column height of 3 /2 to 4 inches in a 1 inch diameter tube. This cor responds to a bulk density of about 5.55 to 7.28 grams/ cubic inch. It has been found that if the bulk density is greater than 7.5 grams/cubic inch, the column is too dense and the blood will not flow properly through the column. If the bulk density is less than 2.5 grams/cubic inch, the fibers will be too loosely packed with the result that the removal of the white blood cells is incomplete. It has been found that with a 1 inch internal diameter tube, at least 12 grams of fibers should be employed in the filter bed.

FIG. 2 illustrates the filter assembly as used in a blood treating system. In this system the needle 6 is inserted within the rubber or flexible stopper 10 of an inverted bottle 11 containing the whole blood, while the needle 9 is inserted within the stopper 12 of a bottle 13 into which the treated blood is to be collected. The bottle 13 is a sealed vacuum bottle containing air at a vacuum of about 26 inches of mercury. When the needle 9 is inserted within the bottle '13, the pressure Within the system will tend to equalize with the result that the blood will be drawn downwardly from the upper bottle 11 through the filter column into the lower bottle 13.

The blood contained in the upper bottle 11 has a pH in the range of 7.3 to 7.5 and contains a small amount of heparin, which serves as an anticoagulant. Alternate ly, the Whole blood contained in bottle 11, instead of containing heparin, may have been initially passed through an ion exchange resin column to remove the calcium ons. In this case the blood would also have a pH in the range of 7.3 to 7.5.

The whole blood contained in bottle 11 passes downwardly through the fiber mass 3 within the tube 1. The blood contains red blood cells having an average particle diameter of about 7 /2 microns and white blood cells having an average particle diameter of 10 to 12 microns. During passage through tube 1, the white blood cells are held by a polar or electrostatic charge to the fibers 3 and there may also be a mechanical filtering action. This process results in the majority of the white blood cells being removed from the blood while the red blood cellS and plasma are not afiected. During the proc s, a p r in the neighborhood of 25 to 50% of the platelets are from the whole blood a well as the white blood cel s.

The white blood cells or leukocytes consist primarily of lymphocytes and neutrophilic segmented cells with the neutrophilic segmented cells making up about 65 to 70% of the leukocytes and the lymphocytes comprising about 20 to 25% of the leukocytes. By use of the process of the invention, substantially all of the neutrophilic segmented cells are removed and a substantial portion of the lymphocytes are also removed.

FIG. 3 shows a modified form of the invention comprising an upper plastic bag 14 containing whole blood with heparin used as the anti-coagulant. The plastic bag 14 includes an inlet tube 15 in which the blood is introduced into the bag from the donor and an outlet tube 16 which is connected to a glass tube -17 extending through a stopper 18 of tube 19 which corresponds to tube 1 of the first embodiment. The tube 19 contains a mass of fibers 20 of the same density and nature as fibers 3 or the first embodiment.

The tube 19 is provided with an outlet nipple 21 which is connected within the inlet tube 22 of a lower plastic bag 23. An outlet tube 24 is also connected to the bag 23.

In the process shown in FIG. 3, the blood from the donor passes by gravity through the inlet tube 15 to the bag 14 where it is mixed with the heparin. The blood is then drawn downwardly through the tube 19 and passes through the fiber filter 20 to remove the white blood cells, and is collected in the lower plastic bag 23 which contains ACD solution as an anticoagulant. The ACD solution is a conventional solution being a mixture of citric acid, sodium citrate, and either glucose or dextrose. In normal practice, the ACD solutions are designated as formula A and B which refers to the concentration of the solution with both formula A and B containing the same ingredients. The ACD solutions do not have to be used if the processed blood will be transfused in less than 24 hours.

FIG. 4 is a second modified form of the system shown in FIG. 3 in which the blood from the door is initially passed through an ion exchange resin to remove the coagulating constituents and heparin is not employed in bag 14. In this structure the inlet tube 15 of plastic bag 14 is connected to a plastic bag 25 containing the ion exchange resin 26 and the bag 25 is provided with an inlet tube 27 which is adapted to conduct blood to bag 25 from the donor. The ion exchange resin is any one of the common cationic resins such as Amberlite IRC-SO, manufactured by Rohm and Haas, or Dowex 50, manufactured by the Dow Chemical Co. The ion exchange resin adsorbs the calcium ions from the whole blood. The calcium ions cause clotting and by removal of the calcium ions, the blood is maintained in a fluid state.

After passing through the bag 25 containing the ion exchanger resin, the blood passes to the upper bag 14. In this embodiment, heparin is not used, for the ion exchange resin serves to remove the calcium ions which cause clotting or coagulation. As in the case of the embodiment shown in FIG. 3, the blood passes downwardly through the fiber column 20 into the lower bag 23 where it is collected in an ACD solution, a CPD solution which is an aqueous solution containing citrate, phosphate and dextrose, or other preservatives.

In FIG. 3, the blood is moved downwardly from bag 14 to bag 23 by applying pressure to the upper bag 14 and pushing the blood downwardly through the tube 19. In this situation blood is drawn from the donor to the bag 14 by a gravity feed.

In FIG. 4, in which the system uses the ion exchange resin pack, the blood is drawn to the upper bag 14 by placing the upper bag in a vacuum chamber called a Hemolator (vacuum-mixing apparatus) so as to draw the blood into the bag. After the blood is collected in bag 14, the bag is removed from the vacuum chamber and pressure is applied to the bag to force the blood through tube 19 to bag 23.

The process of the invention enables the white blood cells or leukocytes to be removed from the whole blood in a very short period of time, less than minutes and normally about 5 minutes, for a pint of blood. This is a substantial reduction in the time required for removal of the white blood cells compared to the time necessary in a centrifugal or sedimentation process which generally requires 2 to 4 hours. Moreover, the apparatus is inexpensive and is a disposable unit so that cleaning and sanitizing operations are eliminated.

The blood produced by the process contains all of the plasma and most of the platelets as well as the red blood cells. Thus, this blood can be used effectively for all the transfusion needs of leukocyte sensitized patients.

No potentially toxic substances are added to the blood and if heparin is employed, it may be readily neutralized by the use of protamine sulfate or polybrene when this is deemed necessary by the physician.

With the process of the invention, the handling of the blood is reduced to a minimum so that the danger of contamination is substantially eliminated, particularly when using the double plastic bag system. The blood produced by the process has a substantially uniform white blood count and the process is predictable in this regard.

If the treated blood is collected and mixed with an ACD solution, survival studies have indicated that this blood can be safety used for a period of at least two weeks. This is a substantial improvement over blood treated by centrifugal or sedimentation processes which must be used within hours after treatment.

We claim:

1. A method of transfusing blood, comprising passing whole animal blood having a pH in the range of 7.3 to 7.5 through a mass of hapharzardly arranged non-absorbent synthetic organic fibers to remove the while blood cells from the blood, said mass of fibers having a bulk density in the range of 2.5 to 7.5 grams/cubic inch, and thereafter transfusing the blood into a human body.

2. The method of claim 1, wherein the fibers are nylon.

3. A method of treating animal blood to remove the white blood cells, comprising the steps of subjecting a quantity of non-absorbent synthetic fibers to the actio of a surface active agent to remove the surface finish from the fibers, compacting more than 12 grams of the fibers in a column having a compaction equivalent to that of grams of fibers packed in a column 1 inch in diameter with a column height of 3 /2 to 4 /2 inches, and passing at least one pint of whole animal blood having a pH in the range of 7.3 to 7.5 through said column of fibers in a period of less than 15 minutes with the white blood cells of the blood being removed by polar attraction to the fibers and by the filtering action of the fiber column.

4. The method of claim 3, wherein the fibers are nylon.

'5. In a method of transfusing blood from a donor to a donee, comprising mixing the Whole blood from the donor with heparin, passing the blood containing heparin through a mass of non-absorbent synthetic organic fibers to thereby substantially remove the white blood cells from the blood, said mass of fibers having a bulk density in the range of 2.5 to 7.5 grams/cubic inch, mixing the blood with a preservative to permit the blood to be stored and used for a period up to at least 14 days, and transfusing the blood to the donee.

6. An apparatus for treating and collecting animal blood, comprising a first container containing a cationic exchange resin and having an inlet to receive whole blood from a blood donor, a first plastic bag, a second container containing at least 12 grams of haphazardly arranged non-absorbent synthetic organic fibers substantially free of surface finish, said fibers having a compaction equivalent to that of 20 grams of fibers packed in a column 1 inch in diameter with a column height of 3 /2 to 4V2 inches, a second plastic bag, and conduit means connecting said first container, said first plastic bag, said second container and said second plastic bag in series whereby blood from said donor can pass through the ion exchange resin in said first container to remove the coagulating constituents from the blood, then through said first plastic bag and through the fibers in said second container to remove the white blood cells from the blood by polar attraction and mechanical filtering and said blood being collected is said second plastic bag.

7. The apparatus of claim 6, wherein the fibers are nylon.

8. A unit for treating and collecting blood, comprising a first container having an inlet and an outlet with whole blood from a donor being introduced into said first container through said inlet, a tubular member containing a mass of haphazardly arranged non-absorbent synthetic organic fibers having a weight of at least 12 grams, said mass of fibers having a bulk density of 2.5 to 7.5 grams/cubic inch, conduit means connecting the outlet of said first container with said tubular member for conducting whole blood from the first container to said tubular member, a second container having an inlet therein, and second conduit means connecting the tubular memher with the inlet of said second container for conducting treated blood from the tubular member to the second container for storage therein, the blood being introduced into said first container having a pH in the range of 7.3 to 7.5 and thereafter passing through said mass of fibers in said tubular member whereby the white blood cells are removed from the whole blood by both mechanical filtering action and polar attraction to the fibers.

9. The structure of claim 8 in which the first container contains a quantity of heparin and the second container contains a quantity of an ACD solution.

10. The structure of claim 8 in which the fibers are selected from the proup consisting of nylon, polyester, polyacrylonitrile, and polytetrafluoroethylene.

11. The unit of claim 8, wherein the fibers are nylon.

12. In a method of transfusing blood from a human donor to a donee, the steps of passing whole blood from the donor having a pH in the range of 7.3 to 7.5 through a mass of haphazardly arranged non-absorbent synthetic organic fibers, said fibers having a weight of at least 12 grams and having a bulk density sufficient to permit flow of one pint of blood therethrough in less than 15 minutes and to remove a substantial portion of the leukocytes from the blood, and thereafter transfusing the blood to the donee.

13. In a method of transfusing blood from a donor to a donee, the steps of haphazardly arranging a mass of non-absorbent synthetic organic fibers in an open-ended container to provide the fibers with a bulk density of 2.5 to 7.5 grams/cubic inch, passing whole blood from the donor having a pH in the range of 7.3 to 7.5 through said mass of haphazardly arranged fibers at a rate equivalent to that of passing one pint of blood therethrough in a period less than fifteen minutes to remove a substantial portion of the leukocytes from the blood, and thereafter transfusing the blood to the donee.

14. The method of claim 13, wherein the fibers are nylon.

15. A filter assembly for treating blood to remove the white blood cells, comprising an elongated container having an inlet opening in one end and an outlet opening in the opposite end, means connected to the inlet opening to introduce whole blood into said container, means connected to the outlet opening for discharging treated blood from the container, and a mass of haphazardly arranged, non-absorbent, synthetic fibers disposed within the container, said mass of fibers having a weight of at least 12 grams and having a bulk density of 2.5 to 7.5 grams per cubic inch, said fibers being substantially free of surface finish and serving to remove the white blood cells by both mechanical filtering and polar attraction as whole blood passes through the container.

nylon.

16. The assembly of claim 15, wherein the fibers are References Cited UNITED STATES PATENTS 8 January 1957, Bulletin X-64, by Technical Service Section, Du Pont C0.

Fleming, British J. Exptl. Path., vol. 7, 1926, pp. 281- 286.

Humphrey, et al., Air Sterilization by Fibrous Media,

223" 55 33 5 Ind. &Ellg. Chem, vol. 47, 1955, pp. 924-930.

J P EBM,1 W33- Stackhouse 21O 500 X 335ohnson, S 02 2 November 1959, pp 3 PPIaCCO 210*446 X Siedentopf et al., Science, Sept. 25, 1942, p. 303. Plccard 5:528 X 10 'Wl'OtrOwski, Chem. Eng. Progress, vol. 53, N 7, July Jackson et a1. 16 /78 X 1957 Pesce 55-528 X Ryan 210-24 X REUBEN FRIEDMAN, Primary Examiner Wandell et al. 23-2585 Great Britain.

OTHER REFERENCES Du Pont, Filter Fabrics at Du Pont Fibers, pp. 110,

5 F. A. SPEARS, JR., Assistant Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,462,361 Dated August 19, 1969 Inventor-(s) Tibor J. Greenwalt and Mieczyslaw Gajewski It is certified that: error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 62 Cancel "ons" and substitute --ions--- Column 4, line 41 Cancel "door" and substitute ---donor--- Column 4, line 56 Cancel "exchanger" and substitute ---exchange;---- Column 5, claim 6, line 68 After "cationic" insert ---ion-- SIGNED AND SEALED Q Am mm mm 1:. sum, as. Awning Offiou Comiasionor or Paton 

